Vapor ejector pumps



Aug. 21, 1956 G. NGLLER ETAL 2,759,661

VAPOR EJECTOR PUMPS Filed April 12, 1952 Fig-7 14' 15 1a 19 17 21 F ig.215

34 Fig.3C 3g lNVEN TOR s HANS GEO/Q6 NOlLE/Q AND G'J/VTSQ REI'CH UnitedStates Patent VAPOR EJECTOR PUIVIPS Hans Georg Niiller, Koln-Sulz, andGiinter Reich, Bad Godesberg, Germany Application April 12, 1952, SerialNo. 282,068

6 Claims. (Cl. 230-95) The invention relates to vapor ejector pumpsusing any desired liquid as driving medium, especially pumps having astraight or converging hollow body arranged in front of the jet at apredetermined distance around the vapor spout and over a predetermineddistance along that vapor spout to permit dilfusion or predeterminedexpansion of the vapor passing the jet, thereby producing a vacuum inthe space surrounding the jet, regardless whether in the pump a spout ofvapor of water, of mercury or oil is formed.

Such pumps have been found to show during operation instabilities in theadjusted pressure value. Experiments underlying this invention haveshown that these instabilities result from the fact that thecross-section of the spout within the ditfusor varies, narrowing downdepending upon varying suction pressure, i. e. the pressure in therecipient to be evacuated.

As a result, between the vapor spout and the inner wall of the diffuserthere is formed a ring-shaped slit through which air, gas or vapor canreturn into the recipient to be evacuated.

It is therefore an object of the invention to provide in a straight orcylindrical difiusor, guiding plates or surfaces which intersect at anangle a plane perpendicular to the axis of the diifusor.

Such guiding surfaces counteract variation in the free cross-section ofthe spout due to varying suction pressure. As a result, the abovementioned slit will be reduced, if not avoided.

These and other objects of the invention will be more fully described inthe drawing annexed herewith, in which Fig. 1 shows in section anexample of realizing the invention as applied to a simple vapor ejectorpump;

Fig. 2 shows another form of guiding surfaces, viewed in the directionof arrows of Fig. l and in a direction perpendicular to the view of Fig.1;

Fig. 3a represents another type of guiding surfaces, also viewed indirection of arrows 10 of Fig. 1;

Figs. 3b and 30 represent side views of certain guiding surfaces shownin Figs. 3a.

In Fig. 1, 11 designates in section a driving jet, to which over line 12in direction of arrow 13, driving vapor from a boiler (not shown) issupplied. Driving jet 11 is arranged in the interior of a tube 14 shapedpartly conically and partly cylindrically. Tube 14 is connected to arecipient (not shown) to be evacuated.

The conical portion 14' of tube 14 is connected to difiusor 15 which isshaped convergent in the direction of the current of the driving vapor.In the interior of diffusor 15, there are arranged two concentric tubes16, 17 of varying length, 16 being shown in section and 17 in full. Tube16 is attached to the inner wall of diffuser 15 by means of radial wires18. Similarly, tube 17 is connected by means of radial metal strips 19to the inner wall of diffusor 15.

Diffusor 15 is arranged inside of vessel 20, also shown in section.Vessel 20 consists of a cylindrical portion 21 having an end wall 22.Inside of vessel 21, 22, there 2,759,661 Patented Aug. 21, 1956 "ice isarranged another substantially cylindrical vessel 23 into which thesmall end of diifusor 15 extends. The space between the inner surface ofcylinder 21 and the outer surface of cylinder 23 is connected to anoutlet tube 24. Box 25 diagrammatically represents a condenser ofotherwise well known construction which is supplied with circulatingcooling water used for the condensation of the driving vapor. Line 26serves to return the condensed driving medium in direction of arrow 27into the boiler.

Tubes 16 and 17 counteract the transversal movement of the vapor spoutwithin diifusor 15 so that the above mentioned instabilities can notoccur anymore.

In Fig. 2 the guiding surfaces are shown to consist of a series ofparallel plates 28-31 which are also parallel to the axis of thediffusor. Plates 2831 are attached to the inner surface of the dilfusor,for example by weldmg.

In the modification of 3a, the guiding surfaces are formed in two setsof plates, a vertical set 32-36 and a horizontal set 3731. Vertical aswell as horizontal plates are attached to the inner wall of dilfusortube 15 in any appropriate manner, for example by welding.

Figs. 3b and 30 show in more detail one of the vertical and horizontalplates 34 and 39, respectively. Both types of plates are of generallytrapezoidal shape. Vertical plate 34, Fig. 3b, has slits 42-46 extendingfrom the two oblique edges and the small base of the trapezium intovertical direction to the top Horizontal plate 39, Fig. 30, has slots47-51 extending from the large base of the trapezium vertically to thebottom. Slots of Figs. 3b and 3c are of different length, as shown.

The plates of Fig. 3b and 3c are slidable one into the other in such amanner that a plate, such as shown in Fig. 30, will he slid from thebottom into a plate, such as shown in Fig. 3b, in such a manner that theplanes of the two types of plates will be arranged perpendicular to eachother.

The description shows that plates 34 and 39, as well as the otherplates, i. e. vertical plates 32, 33, 35, 36 and horizontal plates 37,38, 40, 41 should be constructed in such a manner that they can beassembled with central plates 34 and 39 to an arrangement of guidingsurfaces similar to that shown in Fig. 30.

We claim:

1. In a vapor ejector pump, a jet for passing a vapor spout to produce avacuum in space surrounding the jet, said space being defined by aconical tube coaxial with and surrounding said jet; with a graduallyincreasing diameter from a point behind the opening of said jet to apoint in front of the opening of said jet, thereby causing diffusion ofsaid spout; said conical tube having at its small end an input tube tobe connected to the space to be evacuated, and having connected at itslarge end an output tube; and dividing members supported in said outputtube in the path of said spout and extending substantially in adirection parallel to the axis of said jet so as to permit passage ofvapor with at least a reduction in transversal motion of the vaporparticles.

2. Pump according to claim 1, wherein said dividing members are in theform of concentric tubes having an axis substantially coinciding withthe axis of said jet.

3. Pump according to claim 1, wherein said output tube is a conicaltube, said conical tube extending with gradually decreasing diameterfrom the front opening of the first tube in the direction of the axis ofsaid jet and coaxially therewith.

4. Pump according to claim 3, wherein said dividing members are in theform of spaced parallel plates, arranged substantially in a directionparallel to the axis of said jet.

5. Pump according to claim 3, wherein said dividing 3 members are in theform of two sets of sheets, each set having spaced parallel spacedelements, which are also parallel to the axis of said jet.

6. Pump according to claim 5 wherein said two sets of sheets arearranged to penetrate each other at right 5 angles and are ofsubstantially trepzoidal shape, each having a number of longitudinalslots permitting the elements of said two sets to penetrate each other,thereby subdividing the cross section of said spout into a number ofquadrangular longitudinal channels extending in a 10 direction parallelto the axis of said jet.

UNITED STATES PATENTS Bills May 24, Boeing June 18, Ehrhart Feb. 6, LamnMar. 12, Hickman Aug. 20,

